Influence of yttrium dopant on the synthesis of ultrafine A1N powders by CRN route from a sol-gel low temperature combustion precursor

摘要

Y-doped ultrafine A1N powders were synthesized by a carbothermal reduction nitridation (CRN) route from precursors of A12O3, C and Y2O3 prepared by a sol-gel low temperature combustion technology. The Y dopant reacted with alumina and thus forming yttrium aluminate of A1YO3, A13Y5O_(12) and A12Y4O9, which formed a liquid at about 1400 °C and promoted the transformation of A12O3 to A1N and the growth of A1N particles. Compared with the conventional solid CRN process, Y dopant reduced the synthesis temperature by 150 °C, and A12O3 transformed to A1N completely at 1450 °C. The content of Y dopant had little effect on the synthesis temperature of A1N whereas it influenced the phase of Y compounds in the products. As the Y/Al molar ratio was in the range of 0.007648-0.022944, the particle sizes of Y-doped A1N powders synthesized at 1450 °C were 150-300 nm.